FastAPI cards
Use async endpoints when the work awaits non-blocking I O; sync endpoints are fine for CPU work or blocking libraries.
async and await in FastAPI
Raise HTTPException for expected API errors and register handlers for shared error formatting.
Exception handling in FastAPI
Middleware wraps the ASGI request-response cycle for cross-cutting behaviors such as timing, headers, and logging.
FastAPI middleware basics
CORS middleware tells browsers which frontends are allowed to call your API across origins.
How do CORS settings work in FastAPI?
Authentication is often implemented through dependencies that validate tokens, sessions, or API keys before route logic runs.
How do you handle authentication in FastAPI?
FastAPI resolves declared dependencies for each request and injects their return values into path operations.
How does dependency injection work in FastAPI?
FastAPI builds OpenAPI schemas from type hints, route definitions, and Pydantic models automatically.
How does FastAPI generate OpenAPI docs?
Choose async for non-blocking I O and sync for blocking libraries or straightforward CPU-bound logic.
Sync vs async endpoints in FastAPI
Background tasks run lightweight follow-up work after sending the HTTP response.
What are background tasks in FastAPI?
Response models define the shape of outgoing data, helping validation, filtering, and API documentation.
What are response models in FastAPI?